is my relay circuit right ?

That was my next question... why a relay? ...and why is 9V being use with LED's? It's generally uncommon to LINK the relay contacts with relay power source in a drawing...

There is SO much you are not telling us and we are barely able to help you as a result.

If you have a display... higher current is what you need and probably not much more voltage. If you are using a 9V battery... you are probably killing it in minutes... they are horrible.

pwillard:
That was my next question… why a relay? …and why is 9V being use with LED’s? It’s generally uncommon to LINK the relay contacts with relay power source in a drawing…

There is SO much you are not telling us and we are barely able to help you as a result.

ok i did try the transistor and what happened is that the light of the 7 segment display is so poor, so i decided to use a relay and it’s giving a good light
my schematic is the same as the one that gave me CrossRoads which is this one in the attachement file

Which is the same thing I drew as a schematic.

transistors should work for led segments, but ok, that' another story.

The way you wire (on your drawing) the relay coil is not the way crossroad drew it, and doesn't match the "bottom view" in the image pwillard posted and the schematic he drew . And the way you connected the diode is..... useless ;)

That's why I said "draw it, and show us before you actually wire it" ;)

alnath: transistors should work for led segments, but ok, that' another story.

The way you wire (on your drawing) the relay coil is not the way crossroad drew it, and doesn't match the "bottom view" in the image pwillard posted and the schematic he drew . And the way you connected the diode is..... useless ;)

That's why I said "draw it, and show us before you actually wire it" ;)

yes about the diode your right lol what a mistake i didn't notice

so how can i do it, because my drawing is the one i upload it

look at the bottom views , and look at your wiring, are you sure they match ?

relay.jpg

relay circuit3.jpg

alnath: look at the bottom views , and look at your wiring, are you sure they match ?

yes they do, same as CrossRoads picture 2

I think they do match. The red line to the 7 segment display isn't supposed to be connected to the red line from the battery, and it is supposed to be at NO.

yes, I had a closer look, I think they match. Then..... maybe the transistor is dead and always "on"

alnath: yes, I had a closer look, I think they match. Then..... maybe the transistor is dead and always "on"

it's not, i changed it to a newer one, it's always on !! :SSS

it was on for a reason that i didn't connect the collector of the transistor to GND, now that i did, the relay is always off but when i connect the blue wire in my drawing the display is on !! there is something wrong here !! :S but i can't figure out what !!

firashelou: it was on for a reason that i didn't connect the collector of the transistor to GND, now that i did, the relay is always off but when i connect the blue wire in my drawing the display is on !! there is something wrong here !! :S but i can't figure out what !!

come on, you must not connect the collector to GND !!

which "blue wire" ?

please, make a new drawing from what you have done now, and...try to make it more ...clear than the previous ones ;) then, we'll find out what is wrong

If you are still working with that drawing with the blue line, you are shorting the power supply. Even if you are not shorting the power supply, the blue line does what the relay is supposed to do, so you don't gain anything by doing that. Forget that blue line. Indeed make a new drawing to show what you have now.

If you have the collector to ground, it wouldn't surprise me if the transistor is dead now. Take a good look at the datasheet for that transistor and where what pin is on it. Mark your drawing in such way that you can't miswire it.

alnath:

firashelou:
it was on for a reason that i didn’t connect the collector of the transistor to GND,
now that i did, the relay is always off but when i connect the blue wire in my drawing the display is on !!
there is something wrong here !! :S but i can’t figure out what !!

come on, you must not connect the collector to GND !!

which “blue wire” ?

please, do a new drawing from what you have done now, and…try to make it more …clear than the previous ones :wink:
then, we’ll find out what is wrong

in fact yes the collector to ground, i learn it from adafruit tutorial check the PDF

arduino - lesson - 13 - DC motors.pdf (856 KB)

firashelou:

alnath:

firashelou: it was on for a reason that i didn't connect the collector of the transistor to GND, now that i did, the relay is always off but when i connect the blue wire in my drawing the display is on !! there is something wrong here !! :S but i can't figure out what !!

come on, you must not connect the collector to GND !!

which "blue wire" ?

please, do a new drawing from what you have done now, and...try to make it more ...clear than the previous ones ;) then, we'll find out what is wrong

in fact yes the collector to ground, i learn it from adafruit tutorial check the PDF

hum... check the pdf again, and tell me where they connect the collector to GND :grin:

emitter to GND is OK, not collector ;)

alnath:

firashelou:

alnath:

firashelou:
it was on for a reason that i didn’t connect the collector of the transistor to GND,
now that i did, the relay is always off but when i connect the blue wire in my drawing the display is on !!
there is something wrong here !! :S but i can’t figure out what !!

come on, you must not connect the collector to GND !!

which “blue wire” ?

please, do a new drawing from what you have done now, and…try to make it more …clear than the previous ones :wink:
then, we’ll find out what is wrong

in fact yes the collector to ground, i learn it from adafruit tutorial check the PDF

hum… check the pdf again, and tell me where they connect the collector to GND :grin:

emitter to GND is OK, not collector :wink:

here is the datasheet of the 2N2222
i see it’s the collector to GND

2N2222.pdf (242 KB)

and here is the drawing of my circuit now

firashelou: here is the datasheet of the 2N2222 i see it's the collector to GND

:astonished: where ??? you should stop smoking the carpet XD :grin:

firashelou:
and here is the drawing of my circuit now

the drawing is better :slight_smile:
but it can’t work with collector to GND, you must reverse pins 1<->3 of the transistor
and for the relay, coil is OK, but I think the wire that goes to the segment should be on the other pin (the left one) .

alnath:

firashelou:
and here is the drawing of my circuit now

the drawing is better :slight_smile:
but it can’t work with collector to GND, you must reverse pins 1<->3 of the transistor
and for the relay, coil is OK, but I think the wire that goes to the segment should be on the other pin (the left one) .

ok i did it, i reversed pin 1 to 3 , so that the 3 is connected to GND and when i connect the left pin of relay as you said 7 segment is off but when i reversed it to right it’s on
but still not working because when i put the arduino pin to LOW the 7 segment stays on